org.apache.hadoop.hbase.filter
Interface RowFilterInterface

All Superinterfaces:
org.apache.hadoop.io.Writable
All Known Implementing Classes:
InclusiveStopRowFilter, PageRowFilter, RegExpRowFilter, RowFilterSet, StopRowFilter, WhileMatchRowFilter

public interface RowFilterInterface
extends org.apache.hadoop.io.Writable

Interface used for row-level filters applied to HRegion.HScanner scan results during calls to next().


Method Summary
 boolean filter(org.apache.hadoop.io.Text rowKey)
          Filters on just a row key.
 boolean filter(org.apache.hadoop.io.Text rowKey, org.apache.hadoop.io.Text colKey, byte[] data)
          Filters on row key and/or a column key.
 boolean filterAllRemaining()
          Determines if the filter has decided that all remaining results should be filtered (skipped).
 boolean filterNotNull(SortedMap<org.apache.hadoop.io.Text,byte[]> columns)
          Filters a row if: 1) The given row (@param columns) has a columnKey expected to be null AND the value associated with that columnKey is non-null.
 boolean processAlways()
          Returns whether or not the filter should always be processed in any filtering call.
 void reset()
          Resets the state of the filter.
 void rowProcessed(boolean filtered, org.apache.hadoop.io.Text key)
          Called to let filter know the final decision (to pass or filter) on a given row.
 void validate(org.apache.hadoop.io.Text[] columns)
          Validates that this filter applies only to a subset of the given columns.
 
Methods inherited from interface org.apache.hadoop.io.Writable
readFields, write
 

Method Detail

reset

void reset()
Resets the state of the filter. Used prior to the start of a Region scan.


rowProcessed

void rowProcessed(boolean filtered,
                  org.apache.hadoop.io.Text key)
Called to let filter know the final decision (to pass or filter) on a given row. With out HScanner calling this, the filter does not know if a row passed filtering even if it passed the row itself because other filters may have failed the row. E.g. when this filter is a member of a RowFilterSet with an OR operator.

Parameters:
filtered -
key -
See Also:
RowFilterSet

processAlways

boolean processAlways()
Returns whether or not the filter should always be processed in any filtering call. This precaution is necessary for filters that maintain state and need to be updated according to their response to filtering calls (see WhileMatchRowFilter for an example). At times, filters nested in RowFilterSets may or may not be called because the RowFilterSet determines a result as fast as possible. Returning true for processAlways() ensures that the filter will always be called.

Returns:
whether or not to always process the filter

filterAllRemaining

boolean filterAllRemaining()
Determines if the filter has decided that all remaining results should be filtered (skipped). This is used to prevent the scanner from scanning a the rest of the HRegion when for sure the filter will exclude all remaining rows.

Returns:
true if the filter intends to filter all remaining rows.

filter

boolean filter(org.apache.hadoop.io.Text rowKey)
Filters on just a row key.

Parameters:
rowKey -
Returns:
true if given row key is filtered and row should not be processed.

filter

boolean filter(org.apache.hadoop.io.Text rowKey,
               org.apache.hadoop.io.Text colKey,
               byte[] data)
Filters on row key and/or a column key.

Parameters:
rowKey - row key to filter on. May be null for no filtering of row key.
colKey - column whose data will be filtered
data - column value
Returns:
true if row filtered and should not be processed.

filterNotNull

boolean filterNotNull(SortedMap<org.apache.hadoop.io.Text,byte[]> columns)
Filters a row if: 1) The given row (@param columns) has a columnKey expected to be null AND the value associated with that columnKey is non-null. 2) The filter has a criterion for a particular columnKey, but that columnKey is not in the given row (@param columns). Note that filterNotNull does not care whether the values associated with a columnKey match. Also note that a "null value" associated with a columnKey is expressed as HConstants.DELETE_BYTES.

Parameters:
columns -
Returns:
true if null/non-null criteria not met.

validate

void validate(org.apache.hadoop.io.Text[] columns)
Validates that this filter applies only to a subset of the given columns. This check is done prior to opening of scanner due to the limitation that filtering of columns is dependent on the retrieval of those columns within the HRegion. Criteria on columns that are not part of a scanner's column list will be ignored. In the case of null value filters, all rows will pass the filter. This behavior should be 'undefined' for the user and therefore not permitted.

Parameters:
columns -


Copyright © 2008 The Apache Software Foundation